1. Field of the Invention
The present invention relates to a method for preparing a metallic oxide phosphor, and more particularly, a method for preparing a metallic oxide phosphor, by which nano-sized particles with uniform particle size distribution and improved crystallinity can be obtained.
2. Description of the Related Art
A phosphor is a material exhibiting luminescence characteristics when excited by energy. In general, the phosphor is used in a light source such as a mercury fluorescent lamp and a mercury-free fluorescent lamp, and in various devices such as an electron emission device and a plasma display panel (PDP). Also, along with the development of new multimedia devices, phosphors are expected to be used in wide variety of applications in the future.
Nano phosphors, also referred to as nano-sized phosphors, advantageously exhibit a low light scattering effect and a large specific surface area compared to the contemporary bulk-sized phosphors, thereby improving light emitting properties.
Requirements for nano phosphors include small particle size, non-aggregated particles, and excellent luminescence efficiency. Phosphors made of small and non-aggregated particles usually exhibit a considerable reduction in the luminescence efficiency. To compensate for the reduction in the emission efficiency, one among contemporary attempts has been made to raise heating temperature or heating time, which may, however, result in agglomeration of phosphor particles. That is, the size of the resulting phosphor may exceed nano size regime. Another disadvantage with the contemporary methods for making nano phosphors is a prolonged processing time, which includes mixing, drying, firing, pulverizing, and the like. To overcome the contemporary preparation methods of nano phosphors, various alternative methods, such as, spray pyrolysis methods, and laser crystallization, have been used. These methods generally require, however, high facility costs and operation costs and face difficulties in mass production.